assert/assert.c

   1 /* Copyright (C) 1991-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <assert.h>
  19 #include <atomic.h>
  20 #include <ldsodefs.h>
  21 #include <libintl.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <sysdep.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27
  28
  29 extern const char *__progname;
  30
  31 #include <wchar.h>
  32 #include <libio/iolibio.h>
  33 #define fflush(s) _IO_fflush (s)
  34
  35 /* This function, when passed a string containing an asserted
  36    expression, a filename, and a line number, prints a message
  37    on the standard error stream of the form:
  38         a.c:10: foobar: Assertion `a == b' failed.
  39    It then aborts program execution via a call to `abort'.  */
  40
  41 #ifdef FATAL_PREPARE_INCLUDE
  42 # include FATAL_PREPARE_INCLUDE
  43 #endif
  44
  45
  46 void
  47 __assert_fail_base (const char *fmt, const char *assertion, const char *file,
  48                     unsigned int line, const char *function)
  49 {
  50   char *str;
  51
  52 #ifdef FATAL_PREPARE
  53   FATAL_PREPARE;
  54 #endif
  55
  56   int total;
  57   if (__asprintf (&str, fmt,
  58                   __progname, __progname[0] ? ": " : "",
  59                   file, line,
  60                   function ? function : "", function ? ": " : "",
  61                   assertion, &total) >= 0)
  62     {
  63       /* Print the message.  */
  64       (void) __fxprintf (NULL, "%s", str);
  65       (void) fflush (stderr);
  66
  67       total = (total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1);
  68       struct abort_msg_s *buf = __mmap (NULL, total, PROT_READ | PROT_WRITE,
  69                                         MAP_ANON | MAP_PRIVATE, -1, 0);
  70       if (__glibc_likely (buf != MAP_FAILED))
  71         {
  72           buf->size = total;
  73           strcpy (buf->msg, str);
  74
  75           /* We have to free the old buffer since the application might
  76              catch the SIGABRT signal.  */
  77           struct abort_msg_s *old = atomic_exchange_acquire (&__abort_msg, buf);
  78
  79           if (old != NULL)
  80             __munmap (old, old->size);
  81         }
  82
  83       free (str);
  84     }
  85   else
  86     {
  87       /* At least print a minimal message.  */
  88       static const char errstr[] = "Unexpected error.\n";
  89       __libc_write (STDERR_FILENO, errstr, sizeof (errstr) - 1);
  90     }
  91
  92   abort ();
  93 }
  94
  95
  96 #undef __assert_fail
  97 void
  98 __assert_fail (const char *assertion, const char *file, unsigned int line,
  99                const char *function)
 100 {
 101   __assert_fail_base (_("%s%s%s:%u: %s%sAssertion `%s' failed.\n%n"),
 102                       assertion, file, line, function);
 103 }